The most dangerous task in mechanically driving a post into the ground is initially holding the post in an upright position while it is hammered to start it into the ground. If the top portion of the post is struck off center, or alternatively, if the post is misaligned with the swing of the hammer--the post will slip and fly laterally out from beneath the hammer. A mechanical driver which pounds continuously and with great force presents a grave danger to the individual initially positioning the post. If a top portion of the post begins to slip laterally, before it can be straightened--it will be struck again. When the misalignment is sufficient the post will laterally fly out from underneath the hammer with great speed, force, and energy--severely striking any thing or person in its path.
Another problem with the existing way of pounding a post from a mobile piece of equipment is that it requires two persons. Someone must coordinate and pay a helper for assistance. Pieces of mobile equipment generally have only one auxiliary hydraulic valve provided for auxiliary attachments. The addition of more valves is usually cumbersome and prohibitively expensive.